Hydraulic clutch



D ett. 12, 1.944; .A N THOMAS Re. 22,577

. l HYDRAULIC CLUTCH Original Filed Dec. 2, 1939 4 Sheeis-Sheet 1 'Defl- 12, 1944. A. N. THOMAS v Re. 22,577

HYDRAULIC CLUTCH Original Filed Dec. 2, 1959 4 Sheets-Sheet 2 De12,1944. *A N THOMAS Ra 2.2,5-77

`mmRAULIt: CLUTCH 4 Sheets-Sheet 5 Original Filed Dec. 2. 1939 Dec' 1K2, 1944'. A. N. THOMAS s l Re. 22,577l

y A I HYDRAULIC CLUTCH original Filed Dec. 2, 1939` 4 sneet-sheet 4 Reissued Dec. 12, 1944 Re. 22,577y

HYDRAULIC CLUTCH Albert N. Thomas, Dodge City, Kans., assigner to Thomas Hydraulic Speed Controls, Incorporated, Dodge City, Kans., a corporation of Kansas Original No. 2,329,230Qdated September 14, 1943,

Serial No. 307,207, December 2, 1939. Application for reissue January 20, 1944, Serial No.

22 claims. (ci. 1oz-s1) 'I'his invention relates to new and useful improvements in hydraulic clutches of the type or class wherein the circulation of'fluid mediums, such as oil or-air, or mixtures of both are controlled and regulated by a single valve for governing theirow through the elements of a suitable hydraulic pump incorporated within the clutch casing.

vIn hydraulic power-transmission any powerdriven element such as geared shafting, a belt, or chain drive may be considered as a prime mover, drive member or driving means. The hydraulic clutch herein disclosed is adapted to be interposed as a power-transmitting unit between such driving means and a driven shaft, driven member or driven mechanism.

One of the objects of my invention is to provide a novel hydraulic clutch which is characterized by comparatively high eillciency,gsimplicity of construction, and flexibility in operation and control.

vAnother object of my invention resides in the provision of a novelhydraulic clutch affording a free neutral operation without the use of brake devices for the driven member. This attainment of free neutral operation is made possible through the novel valve and port constructions and arrangement of cooperative parts whereby fluids, including air and oil, are in certain operative positions of the valve utilized independently of one another and, in other positions of the valve, in progressively varied mixtures.

Another feature of my inventionis found in the provision of a hydraulically and mechanically balanced clutch mechanism, including a single slidable cylindrical valve, pressure stabilizing means interconnecting all of the intake ports, andA pressure-stabilizing means interconnecting all of the exhaust ports whereby the pressures and vacuums acting upon the pump elements and valve are balanced, thereby obviating the disadvantage of unequalized pressure or vacuum action upon the valve.

With the` above and other objects in view, In invention consists in the novel combination, construction, and arrangement of the parts andl members shown in preferred embodiment in the 'attached drawings. described in the following specification, and particularly pointed out in the appended claims.

The invention will be readily understood by referenceto the accompanying drawings in which trated.

`In the drawings:

a typical embodiment thereof has been illus-` `Fig. 1 is a diagrammatic plan view of a hoist showing one application of a hydraulic clutch embodying my invention; l

Fig. 2 is a longitudinal section of the clutch taken on line 2--2 of Fig. 1, showing the valve in full neutral or open position;

Fig. 3 is a longitudinal section of the clutch corresponding to Fig. 2 shown in -full closed po sition with no over-run; l

Figs. 4, 5, 6, and 'l are `cross-sections of the clutch taken respectively on lines 4-I, 5-5, 6 8, and 1-1 of Fig. 3;

Fig. 8 is a diagrammatic illustration of the clutch showing the valve moved to a position wherein a portion of the circulating air has been replaced by the oil;

Fig. 9 is a diagramma ic illustration of the clutch showing two successive positions of the valve. `'I'he valve position shown by the heavy broken lines showing the valve moved further inwardly fromv the lposition shown in Fig. 8

` wherein the intake and exhaust ports of the pump are aboutl half closed. The valve position shown by the lighter dot and dash lines showing still a further inward movement of the valve;

1 Fig. 10 is a longitudinal section through one of the lpressure by-pass valves; Fig. 11 is a longitudinal air expansion relief valve.

Referring to Fig. 1, the diagrammatically shown hoist consists of a suitable engine l5 which is provided with a suitable clutch (not shown) operable by arm I8` through the link l1 and arm I8 which is fixed to the shaft I3 shown supported section through the in bearings 20. The shaft I9 is also operatively to a holding brake 22 mounted about the hydraulic clutch 23.

The enginel drive shaft '2l as shown is proover .which is trained sprocket 21 fixed` The inner end of shaft 23 is shown connected to the clutch 23 as by means of a flange 23 and cap screws 30.

The service reel 3| is fixed to the clutch driven shaft 32.

The clutch is provided with a grooved valve op'- erating sleeve 33 slidable with its supporting rods 12 on the clutch about the driven shaft 32. The sleeve 33 is slidable into clutch-operating positions by a` lever 34 pivoted at 35 and having a forked end 36 disposed in the grooved sleeve 33 and its opposite end is connected by a linkl 31 to the lower end of the pivoted'clutch-operatin! lever 33.

engage the engine clutch (not shown) and that further continued depression oi foot pedal through arm 2| will cause the holding brake 22 to retain the clutch casing against rotation.

Assuming engine I5 is in operation and the clutch valve-operating lever 38 is in open position and the foot pedal 44 is in raised or inoperative braking pos1tion,`the drive vshaft 24 will impart rotation .to the casing of clutch23 bymeans of the sprockets 25 and 21 and the drive chain 28.

In such operation, the emergency brake 38 will of y course rest in inoperative position.

When the clutch 'valve-operating lever 38 is moved'to the left as shown in Fig. l, the clutch valve, in response to such movement of lever 38.

will be moved progressively toward closed position and the reel 3| will be rotated at-progressively increased vspeeds until the fully closed valve position is reached whereat the reel 3| will be substantially synchronized in rotation with the clutch casing. .Assuming now that an object is being raised by a wire-rope cable trained around the reel 3l and suitable guide sheaves and that the desired raised position 'oi the object has almost been attained, the clutch valve-operating lever '38 is then moved back toward open position until the object comes to rest at the desired raised position and at such moment of rest the developed torque balances the weight of the object The reel 3l is provided with an emergency' metal having ,port areas cored or machined to suit the operating., requirements.

`The gear pumps-casing 45 consists of a cylindrlcal wall 45A, thre radially disposed ribs 45B terminating in arcuately arranged heads 45c delining a well for the primary gear 46 'which is splined or keyed to the inner end of the driven shaft 32. ,These arcuate walls 45c are disposed for close lit around the periphery of the teeth of the primary gear 4.6 and constitute compression walls for the uid or iluids passing through the Two or more circularly equally spaced secondary gears 41 are provided which are in mesh with the primary gear 48. I have preferred to show three of such secondary gears 41 but one or more m'ay be used. The secondary gears are each positioned in a well dened by a pair of loppo'sitely I compression Wall and their extreme inner ends brought to rest. A further movement of the lever 38 toward open position will cause a lowering of.

if such object is brought to rest in balanced position and such emergency brake 38 has not been brought into braking operation, the suspended balanced object may with slight effort be manually raised or lowered or spotted at the desired precise elevation.

If the foot pedal 44 is fully depressed, the arm I8 will act to disengage the engine l 5 from oper-'- f 'ation of the shaft 24 and the clutch 23 and, at

the same time, the holding brake` 22 will be brought into braking operation with the casing of the clutch 23.v In such operation the hydraulic clutch 23 may be used as a hydraulic brake, the rate of descent of the suspended object being controlled by lever 38 whereby open position of v the clutch valve will permit full speed lowering and full closed position of the clutch valve will ybring the object to a stopped suspended position.;

The operator maychange from hydraulic braking operation to clutch operation by proper manipulation of levers and 38, or may use operatlng lever 43 incombination with operating levers 44 andV 38.

' Referring now to the clutch illustrations shown I in Figs. 2. 3, 4, 5, 6, and "I, my improved clutch 23,

as preferably Vshown in these illustrations, con- I ts of gear pump casing 45 preferably of cast curvedface wall extensions 45D formed. like the ribs 4I B,.integrally with the annular wall 45A.

In the construction of the casting 45 as here shown in Fig. 5, the spaces 63 and 64 between the portions 45B, 45C, and 45D are clear openings extending through such casting and constitute,` respectively, the intake and exhaust chambers.

The pairs of walls 45D constitute a circular are disposed a spaced distance from the periphery of the primary gear 46 and the adjacent end of wall 45c to provide inletv and outlet passages for the circulating fluid therebetween.

The gear pump casing 45 includes an exterior circular metal wall or head 48 to which the flange 28 of the drive shaft 28 is secured by the cap screws 30. Forl patent purposes the shaft 28 may be termed es a prime mover or driving means and rotary power could also be applied directly to the clutch housing 53 as by a belt or gearing.

The inner face of the pump casing 45 is provided with a circular metal port or manifold plate 48.

These plates 48 and 48 are preferably formed with circular alignment rims, `respectively 48A and 48A. which are adapted to be seated in machined grooves of the casting 45. Sealing means providing fluid-tight joints, such as suitable gasprovided with suitable bearings 58 and the ends of their supportingpins 5l extend into suitable circular recesses formed in the head plate 48 and the port plate 48. Each secondary gear is provided with a suitable oil hole 414.

The head plate 48 is also providedwith a cen-- tral circular recess which is adapted to receive a pilot ball-bearing 52 for the inner end of the driven shaft 32 whichvas shown in Figs. 2, 3, and

5, is of decreased diameter at such bearing sup port. The drivensuhaft 32 extends through al close fitting opening n the' center of the'port plate 48. l Y

The casing 46 and the plates 48 and 49 may be Vtermed the fluid 'pump casing.

MyV improved clutch, which is generally indicated by 23, also includes the outer cylindrical' wall or casing 53 which as here preferably shown is formed with inwardly right-angularly disposed integral end flanges 53^.

'I'he port plate 48 is preferably provided with a circular recess'whieh constitutes a seat for the inner ange 53A.

The pump casing, which includes the casing 45 and plates 48 and 48, is securely mounted to the flanged inner end of the exterior casing" il by bolts Il and cap screws ll'. The casing 58 together with the port plate 48 and the'end closure head or plate 55 constitutes the valve housing and fluid receptacle and suitable cap screws 58 securely hold the closure head l to the flange 53^. The head 55 and port plate I8 are circularly recessed for the flanged ends l8^ of the casing I3 to facilitate alignment of these parts, as shown in Figs. 2 and 3.

A suitable screw plug 51 is provided for. the inlet opening through which the clutch reservoir 88 is properly filled with av suitable oil of the desired viscosity. Oils of a wide range of viscosity are adaptable for use in this type of clutch.

The end closure head 58 is cast with anin-V wardly disposed integral hub 55A which is adapted to support a ball-bearing 58 for mounting of the driven'shaft 32 and a suitable screw type packing gland nut 58 is-provided as shown in Figs. 2 and 3.

The port or manifold plate 48 is preferably providedwith a circular rim 8l about which is seated the hollow cylindrical valve seat-82. The valve seat 02 is welded or otherwise secured to 211e rim 8| or may be formed integrally there- Assuming that. the rotation of the clutch is anti-clockwise as indicated by the arrow in Fig.

5, the intake ,chambers of the gear pump are` indicated by numeral 88 and the exhaust chambers by I4.

The port plate 48 is provided with intake open ings 85l and exhaust openings 88 to which are secured, in any suitable manner, the intake and exhaust conduits or pipes respectively indicated by 81 and 68. These intake and exhaust conduits are disposed within the oil reservoir 88 and terminate in curved ends which are secured to the hollow cylindrical valve seat 82 which'is provided with openings in register with such curved ends.

o! circularly spaced elongated openings 18G- to permit. the passage ofoil therethrough as and when the valve 10 is moved from neutral toward closed position.

The valve 10'is provided with a pressure-stabilizing port 10H in the form of an annular recess situated in the outside face of the valvevportion 1liA which is operative when such valve is positioned in closed or partially closed position.

The closed position of the valve 1li and the function of such port 18H interconnecting the three exhaust conduits B8 is illustrated in Fig. 3.

When the valve I0 is in fully open or `neutral position the exhaust conduits B8 have unrestricted discharge through the valve seat 82 and the intake conduits 61 communicate with port Z for free passage of air through openings A1|)1 'and these conduits 81 are interconnected by the pressure-stabilizing port 82D, as illustrated in Fig.

3, for stabilization of pressure in the event'of reverse rotation of the clutch casing relatively to shaft 32.

The discharge ends of the exhaust conduits 88 communicate with openings 82C which extend through the valve seat 82 and the openings 82C are circularly plane-aligned.

The inlet ends of the intake'conduits s1 communicate with the annular stabilizing port 82D formed in the inside face 'of the valve seat 62.

The valve seat 82 is also provided with a plurality of circularly spaced elongated openings 82B to permit oil or air to escape into-the chamber I8.- The outerl or free end of the valve seat 82 is spaced fromthe inside face of the end closure plate 88.

sudabiy mounted within the valve seat s2 is a hollow cylindrical valve 18 which consists of the pair of spaced cylindrical wall sections 1|)A and 18B having, spaced annular walls 18 and 18D. These walls 18C and 18D are disposed preferably right-angularlyto their respective intgeral cy iindrical valve sections lliA and 18B and extend l inwardly to a spaced distance from the shaft 32.

The walls 18 and 10D are integrally connected by acylindrical' transverse wall 1li! which is of a diameter less than the diameter of the valve sections 1|I^ and 10B and is provided with a plurality of circularly spaced elongated openings 1l to permit the passage of air therethrough for' free neutral operation'of the clutch when valve 1l is in the position shown in Fig. 2.

' Sealing rings 'II may be used to secure a more perfect or fluid-tight joint between the slidable valve and its seat n.

The valve 1l is also provided with a plurality ing 15.

Under such free neutral operation the shaft I2 will remain in stationary position.

The valve operating sleeve 38, which is adapted to be shifted into-various desired operative positions of the valve 1li by the lever 38, is connected to the valve 10 by the circularly spaced rods 12 which extend through the packing gland nuts 18.

The .exhaust conduits 88 are preferably provided with bypass valves 14. See Figs. 2, 3 and l0. These valves 14 are screw-connected to the exhaust conduits and are adapted to relieve the pump of any excessive pressures which might be caused by unforeseen or accidental overload transmitted to the clutch and are provided with adjustable pressure-regulating plugs whereby the maximum working pressure of the pump may be altered when the clutch is in stationary po-` sition.

Any suitable spring-pressed overload valve .may be used. I have preferred to construct thevalve 14 as shown in Fig. l0 wherein the open end casng.15 is provided witha plurality of exhaust openings 18 normally closed by the piston valve 11 which is retained in closed position at rest uponthe valve seat 18 by the coil spring 18 mounted upon the valve stem 80. One end of the spring 19 is in abutment with the valve 11 and its opposite end is confined within the cylindrical cavity 8| of the adjustable pressure-regulating plug 82 screw-mounted within the cas- Undue excessive uid pressures transmitted to and through the exhaust conduits may be automatically reduced by actuation of same against 4the spring-pressed valves 11 to permit escape of the fluid through openings 18.

As heretofore indicated, the Aoperation of my clutch makes usev of both air and oil fluid in diier'ent operations as where air. is used solely for free or neutral operation, and in other operations where varied proportions of air and oil mixtures; or solely oil, is used as the powervtransmitting control medium. I

It will be v`understood'that the ou reservoir Vsu is not fully filled with 011. The amount of oil employed is determined by the diameters of the central openings in the walls 18C and 10n.

When the clutch is rotated the body of oil therein will, by centrifugal force, be caused to assume an annular shaped body adjacent the clutch casing Il thereby producing an air space or inner. core of air surrounding the driven shaft 88. The divtding surface between the air and oil tedinlllgzhythelinexfrom Y observed that the port Z, de 1D0 and 10D which project inmdbilrough the body of oil into the central vair constitutes under normal operation an airport, as clearly shown in Fig. 2.

The space between the shaft 32 and the ciry cular edges of walls 10 and IIID defining' the opening around the shaft 32 must be large enough to allow a free movement of air'around the shaft I2 when the pumpgears are operating at their maximum speed under free neutral operation when shaft 321s at rest.

An important feature of my invention is found in the provision ofthe centrifugally actuated'air relief valve kIl which is designed to operate only Y whenl the clutch is in rotation to permit air communicationbzetween the interior of casing ll and the exterior atmosphere for the purpo of Areducing any undue air pressure caused by the expansion of the air within the casing under heavy duty operation.

The valve, Il consists of a tubular casing I4 connected by the .elbow l5 with a pipe nipple Il the inner end of which communicates with the air passage l1 drilled within the inner side portion of the wan 55 hear the hub 55A.

The inlet opening 8B is provided-with a valve seat 89 normally supporting the piston valve Il for normally closing the transverse air discharge openings 9|. The valve Il is provided with a valve stem 02 of reduced diameter about which is mounted the coil spring 93 one end'of which' is in ab utment with the valve 80 and the other end of which is in abutment with the bolt Il which may be adjustably inserted through any space one of the pairs of transversely aligned openings 8l to thereby vary the pressure of said spring 93 against the valve I0.

The spring 93 is preferably. a comparatively l light spring to insure opening' of the valve Il upon a predetermined speed of rotation of the clutch. v

It will be understood that the manifold plate u, valve seat s2 and the intake and 'exhaust conduits could be cast in one piece.

In apparatus not subjected to over-running,

the valve portion 10B may be dispensed with.

As shown in Fig.'2, the valve 1D is in its ex- 'tremeouter position. Assuming that rotary torque exceeds the load imposed upon the driven shaft II.

In Fig. 9, two successive inward'movements of valve 'Il are shown. 'I'he position of the valve y sible through the pump since all lexhaust conv one port system or the other.

power is applied to the shaft Il, the clutch'cas- `lng 53 together withrthe attached pump casing v`will be rotated but the shaft 32 will be inoperative for power transmission, that, is, the clutch 2l is in free neutral or open position sinceV only air from the central portion of the clutch is being admitted through openings 101' `f'and port Z into the intake conduits 61. s

Under such neutral operation the air passed through the pump is insufficient to constitute. for practical operative purposes, the necessary resistant between the primary and secondary pump gears to cause power rotation of` the shaft 32 and therefore the secondary gears I1 will be free for planetary rotation about the stationary primary gear Il. I I'he valve 10, as diagrammatiaclly shown in Fig. 8, is moved slightly inwardly to such posi-r tion where a small: quantity of oil is being admitted for armixture with the air through openings 10G intothe intake' conduits M to provide a slight resistant between the secondary and primary gears to thus transmit asmall amount of torque and rotation to shaft ,fplovided auch 1l shown by the heavy, broken lines shows'the valve inovedslightly further inwardly from the position shown in Fig. 8 wherein about half air and half oil is passed into the intake conduits thus materially increasing the amountl of power and rotation transmitted to shaft l2.

The position 'of the valve 'III shown by the lighter dot and dash lines in Fig. 9 indicates the initial high position of valve 'Il wherein the maximum of power and rotation is transmitted to shaft 32 because no circulation of oil is posduits are fully closed withthe result that the oil in the pump becomes a resistant to interlock the primary gear with the secondary gears to thereby cause an intel-locked rotation of the clutch housing with shaft I2.

It will be observed from the illustrations in Figs. 2 and 3, that the valve 'l0 is adapted to be moved inwardly to a position whereat only oil is being admittedinto the vintalie conduits il for circulation through the pump and out of the partially openaexhaust openings 62, vsuoli position of the valve l0 preceding the movement of the valve to the position shown bythe dot and dash lines in Fig. 9.

When the valve 'Il is moved Ato an objectbalancing position, as heretofore described, the

torque developed by the working pressure of the clutch is equal to the torque imposed upon the reel by such balanced object. f

The position oi the valve I0 shown in Fig. 3'

shows the valve Il in full high and no overrun' e position whereinA all intake and exhaust conduits are fully closed by the'valve 'IILv This .isl

the innermost position the valve 1U is ever moved vto and there is no movement or circulation of uid and no relative rotation of the component parts of the pumping elementseven through the driven shaft tends to exceed the driving speed of rotation of shaft 2B. other than the amount of rotation' 'necessary to build up pressure in Only a fractional part of one revolution of relative rotation would be theamount of slack when the valve In is in this position.

Various changes in and modification of the structural details and arrangement of the parts and members maybe readily made by those skilled in theA art to which this invention relates without departing from the spirit of the invention embodied in the appended claims hence I do not wish to be understood as limiting myself lto the exact details and arrangement shown in thel accompanying drawings which are illustrative of one form or embodiment of my invention.

I claim: l

l. In combination, rotary power-driven means,v

a driven shaft, and a hydraulic power-transmis-h sion mechanism operatively connected to said power-driven means, said mechanism including a rotatable casing having a chamber therein partially filled with oil, rfluid pumping meansl operatively connected with said casing, said driven shaft extending into saidl casing and being operatively connected to said fluid pumping means, a uidjntake passage, an exhaust passage, said -es communicating with said fluid pumping means and said chamber, and an Y axially slidable valve for controlling fluid circulation through said passages and said pumping means actuable to permit inow and outflow of air or oi mixtures of air and oil or of oil or ofneither through said passages and said pumping means to thereby control the stationary position or relative rotations of said driven shaft during the rotation of said power-driven means.

2. In the combination as embodied in claim 1 and including centrifugally responsive means providing an outlet for the air within said chamber during the rotation of the casing.

3. In the combination as embodied in claim 1 and including a centrifugally and pressure responsive valve providing an outletl for the air within said chamber upon expansion oi the air during the rotation oi the casing, and pressure responsive outlet means for the exhaust passage interposed between the pumping means and the valve.

4. In vthe combination as embodied in claim 1 said mechanism havinga plurality of said fluid,

intake passages, a. plurality of `said iiuid exhaust passages, and pressure-stabilizing ports, one connecting the discharge ends of all of said exhaust passages, and another the intake ends of all of said intake passages, during .partially and -iully closed positions of said valve.

5. In the combination as embodied in claim l said mechanism having a plurality of said iiuid intakepassages, a plurality of said uid exhaust passages, pressure-stabilizing ports, one connecting the discharge ends of said exhaust passages, and another the intake ends of said intake passages, during partially and fulhl closed positions of said valve, and means providing an outlet into the atmosphere for the air within said chamber during rotation of the casing.

6. A hydraulic clutch adapted to be interposed as a power-transmission mechanism between rotary power-driven means 'and a driven shaft, said clutch comprising a rotatable casing operatively connected to the power-driven means and having a chamber therein partially filled with arrest, or to progressively regulate the inilow and outiiow of air or of mixtures of relatively varied proportions of air and oil or of oil through said conduits and said pumping means to .thereby control the stationary position or relative 'rotations of the driven shaft during the rotation of n said power-driven means and clutch casing.

8. A hydraulic clutch as embodied in claim 7 i and vincluding a pair of radially disposed spaced annular walls dividing said cylindrical valve into two sections to provide a port therebetween which is adapted during the rotation of the clutch casing, in clutch neutral or open position, to provide communication between said intake conduits and the air in the central portion of the casing chamber.

Y 9.- A hydraulic clutch as embodied in claim '7l said valve having an annular pressure-stabilizing recess adapted to interconnect all of said fluid exhaust openings, and said valve seat having an annular pressure-stabilizing recess adapted to interconnect all of saidiiuid intake openings during partially and fully closed positions of saidv valve.

10. A hydraulic clutch as embodied in claim 7 said valve having an annular pressure-stabilizing recess adapted to interconnect all of said iuid exhaust openings, said valve seat having an' annular pressure-stabilizing recess adapted to in terconnect all of said fluid intake openings during partially and fully closed positions of said ,'valve,

and a valve adapted, during the rotation of the clutch casing, to provide an outlet into the atmosphere for the air within the casing chamber.

11. In the combination as embodied in claim l and including a centrifugally and pressure responsive valve providing an outlet for the air within said chamber upon expansion oi the' air ou, nula pumping means within said casing. said driven shait extending into said casing chamber and being operatively connectedr with said pumping means, a cylindrical valve seat within said chamber having a iluid exhaust opening and a iiuid intake opening therein, conduits connecting said valve seat exhaust and intake openings with said fluid pumping means, and a single cylindrical i valve bodiLv slidable within said valve seat adapted upon actuation to entirely arrest, or to progressively regulate the inflow and outflow oi air or of mixtures o! relatively varied proportions of air and oil or oi oil through said conduits and saidv pumping means to thereby control the stationary position or relative rotations of the driven shaft during the rotation of said power-driven means and clutch casing.

l'1. A` hydraulic clutch adapted to be inter posed as apower-transmission mechanism between rotary power-driven means and a driven said valve seat adapted upon actuation to entirely I during the rotation of the casing.

12; A hydraulic 'clutch 'adapted 'to be interposed as a power-transmission mechanism between rotary power-driven means and a driven shaft, said clutch comprising a rotatable casing operatively connected to the `power-driven means and having a chamber therein partially illled with oil, fluid pumping means within said casing, said driven shaft extending into said clutch chamber and being operatively connected to said pumping means, ,a cylindrical valve seat Within said chamber having. a plurality of fluid exhaust openings and a plurality of iiuid intake openings therein, conduits connectingl said valve seat exhaust and intake openings with said fluid` pumping means, and a single cylindrical valve movably mounted on said valve seat adapted upon actuation to entirely arrest, or to progressively regu oil through said conduits and said pumping means to thereby control the stationary position or relative rotations ot the driven shaft during the rotation of said casing.

1,3. A hydraulic clutch asembodied in claim 12 including pressure-stabilizing ports, one connecting the fluid discharge passages and another connecting the fluid intake passages; during partially l and fully closed positions of said valve.

14. A hydraulic clutch as embodied in claim l2 and including an oil inlet in said valve, and an annular walled port in said valve which is adapted during the rotation of the clutch casing, during neutral or partially closed positions of the valve,

toprovide communication between said intake conduits and the air in the central portion of the casing chamber while the exhaust conduits are power-driven means and clutch in communication with the casing fluid chamber through their' discharge openings. in the valve seat, said valve being adapted to be moved to progressively close said intake and exhaust conduits tocause a. relatively increased rotation of the driven shaft until'the rotation of the driven shaft is substantially synchronized with the rotaaan?? tion of the clutch casing whereby during such I progressive closing movement of thevalve the amountof air admitted into said intake conduits is progressively decreased and the amount of oil admitted through said valve inlet into said intake conduits is progressively increased until only oil maybe admitted into said intake conduits while said exhaust openings are still partially" open and where upon the complete closure of the exhaust openings the driven shaft will be interlocked in substantially synchronized rotation with the clutch casing.

15. A hydraulic power-transmitting mechanism comprising a rotatable power-driven casing having a chamber partially illled with oil, said oil assuming an annular form during the rotation oi the casing to provide a central core of air within the casing, pumping means within said casing. a driven shaft extending into said chamber, said driven shaft being operatively connected to said pumping means and said pumpins means being operatively connected to said casing, a. cylindrical sleeve within said oil chamber having an intake opening and an exhaust opening located in a transverse plane spaced axially from said intake opening, enclosed passages connecting said openings with said pumping means, a cylindrical valve movably mounted on said sleeve,

said valve having an air inlet port and a separate oil inlet spaced axially from said air inlet port. and means for moving said valve, said valve being normally positioned in neutral position to permit passage of only air through said air inlet port into said sleeve intake opening whereby said driven shaft is .maintained in stationary position and said valve being 'movable to ,progressively decrease the now of-air and simultaneously increase the iiow oi oil into 4said sleeve intake opening until only oil is admitted into said sleeve intake opening, and said valve being thereafter movable to a position wherein both oi the sleeve inlet and exhaust openings are closed to the flow of oil or air therethrough.

16. A hydraulic clutch adapted to be interposed between rotary power-driven means and a driven shaft.' said clutch comprising .a rotatable casing operatively connected with said power-driven means and having a chamber therein partially illled with'oil whereby, during the rotation of said casing, there is provided in said chamber an outer annular zone of oil'and an inner central zone oi' air, iluid pumping means operatively connected with said casing and with said driven shaft, iluid intake and ex,-

haust passages communicating with said uid pumping means and said chamber, movable uid control means disposed within said chamber and extending from said outer annular zone or oil into said inner central zone of air, and actuable to control the iiow of air. or of mixtures oil air and oil, or of oil through said passages and pumping means to thereby control the stationary position or relativelyvariable rotations oi said driven shaft during the rotation of said power-driven means.

17. A hydraulic clutch adapted to be 'intera posed between rotary power-driven means and a driven shaft, said clutch comprising a rotatable said casing by casing operatively connected withsaid powerdriven means and having a chamber therein partially filled with oil whereby, during the rotation of said casing, there is provided 'in said chamber an outer annular zone of oil and an inner central zone of air, uidpumping means operatively connected with said casing and with said driven shaft, a plurality oi iluid intake passages, a lplurality of exhaust passages. said passages communicating with said fluid pumping means and said chamber, movable valve-means disposed in both of said zonesand movable in both of said zones to control the ilow of air, or of relatively proportionately varied mixtures of air and oil, or of oil, or of neither through said passages and said pumping meansf during the rotation of the casing while the iluid' of the lower resistant value is disposed in a central inner zone of said chamber, iiuid pumping means rotatable with saldi casing having certain component parts operatively connected with said casing and other component parts operatively connected with said driven shaft, huid intake and exhaust passages communicating with said pumping means and said chamber, uid circulation control means including movable valve means and uid by-pass means adapted to limit the maximum torquey of said driven shaft, said movable valve meansextending from said outer zone into said central inner mae and being actuable to control the now of the fluid o! lower resistant value, or of mixtures of both ofusaid iluids. or of the iluid of the higher resistant value. through said passages and said pumping means to thereby control the stationary position or relatively variable rotations of said driven shaft. said iluid by-pass means including a housing in communication with the compression side of the uid circuit and spring-pressed pressure-responsive means in said housing normally preventing e of iluid through said iiuid by-pass means,

said pressure-responsive means being automatically actuable, after said movable means has been moved to a closed position, to regulate the volucasing, to change the spring tension of said pres-v sure-responsive means to thereby alter the value -of the maximum torque ot said driven shaft.

19. A hydraulic clutch as deilned in claim 18 and including a plurality of exhaust passages and a plurality of said iiuid by-pass means, one

of said iiuid by-pass means belngoperatively connected with each oi' said exhaust passages, the volumetric capacity of all of said by-pass means limiting the working pressure oi the 'liuid' in said pumping means to a maximum pressure wlthinthe range of adjustability of said adjustable means. v

20. A hydraulic clutch as dened in claim l,

theoilinsaidcasingassumlngan annulai-body within an outer zone of said chamber during the rotation of said casing to thereby provide an inner zone of'air, and said axially slidable valve comprising a cylindrical member disposed within said oil zone and having an air inlet port extending from said oil zone into said air zone and an oil inlet disposed within said oil zone adjacent the outlet end oi said air inlet port, the end portions of said cylindrical' member extending axially in opposite directions beyond said air port and said oil inlet, one of said end portions being adapted to progressively close said exhaust passage, and said fluid intake passage being adapted to be closed by the' other end portion after said exhaust passage has been fully closed to thereby sponsive valve for said port entirely arrest the iiow of iluidinto and from said pumping means to thereby cause said driven .shaft to be substantially interlocked for rotation with said casing.

21. A hydraulic clutch as defined in claim 16 including fluid by-pass means adapted to limit the maximum working pressure of the iluid in said pumping means and to by-pass therethrough uid from said pumping means into said chamber, said fluid by-pass means including a, housing in communication with the compression side of the uid circuit and spring-pressed pressure responsive means in said housing adapted to prevent flow of 'iiuid through said uid by-pass means, said .pressure-responsive means being automatically actuable, after said movable fluid control means has been moved to a closed position, to regulate the ilow oi the oil solely through said iiuid :by-pass means in response to a demand torque of a value -at least equal to the maximum torque of the driven shaft and a variation in v '7 speed of the clutch casing relatively to the speed of the driven shaft, and adjustable means on said fluid 'ny-pass means adapted for movement, when -the clutch casing is in stationary position, to change the tension of the springs of said lay-pass means of the iluid in said pumping means. 22. A hydraulic clutch as deiined in claim 1'1 including a iluid by-pass port for eachA of said exhaust passages, each port having an inlet openvingvin communication with the exhaust passage and an outlet spaced from said inlet and consistingof at least one outlet opening, a pressure-readapted to close said inlet and outlet openings,a spring for yieldingly retaining said valve in closed position closing said inlet and outlet openings, and adjustable means for varying the tension'ofsaid spring, said pressure-responsive valves being adaptedto limit the maximum working pressure said pumping means and to permit ilow ovonly oil from said pumping means through said [port outlet into said chamber in response toia demand torque of a value at least equal to the maximum torque of said driven shaft upon and in response to the movement of said movable valve control means to a position closing all outlets of said exhaustA passages -but maintaining said intake pas- Sages open to permit flow of fluid into said pumping means, said pressure-responsive valves being automatically actuable whilelsaid control means is maintained in said closed position to regulate the volumetric ow of the oil through said port outlets during a variation in speed of the clutch casing relatively to the speed of the driven shaft.

ALBERT N. THOMAS.

to thereby alter the maximum working of the fluid in 

